Fix qw syntax error

Fixes syntax error:

    urxvt: perl hook 0 evaluation error: /usr/lib/urxvt/perl/tabbedex: syntax error at /usr/lib/urxvt/perl/tabbedex line 669, near "$hook qw(start destroy user_command key_press property_notify add_lines)"
    syntax error at /usr/lib/urxvt/perl/tabbedex line 681, near "}

    }"